1. Field of the Invention
The present invention relates to a cushion clip. More particularly, the present invention relates to a cushion clip that is attached to an attachment hole formed in a stationary member while the cushion clip is positioned between the stationary member and a movable member so as to absorb an impact that can be produced when the movable member moves toward the stationary member.
2. Description of Related Art
This type of cushion clip is already known. Generally, in such a cushion clip, a cushioning portion that is capable of absorbing an impact is integrated with an engagement portion that is capable of engaging with an attachment hole formed in a stationary member. Further, in the cushion clip thus constructed, the cushioning portion is formed of a soft resin material and has a hollow and substantially cylindrical shape. When a movable member moves toward a stationary member, the cushioning portion of the cushion clip is elastically deformed and compressed between the stationary member and the movable member. As a result, the impact can be absorbed. Thus, the cushion clip is capable of providing an impact absorbing function.
The cushion clip may preferably be used to absorb an impact that can be generated when a door (cover) of a glove box of a vehicle is closed. The cushion clip used in the glove box may provide following functions in addition to the impact absorbing function.
(1) The cushion clip can prevent the door of the glove box from vibrating while the vehicle is moving.
(2) The cushion clip can prevent the door from directly contacting the glove box even when the door is strongly pushed by hand or elbow of a passenger or the like, so as to prevent noise generation and damage of the door and/or the glove box.
(3) The cushion clip can absorb a dimensional error of the door so as to prevent rattling of the door resulting from its inaccurate positioning due to the dimensional error of the door.
(4) The cushion clip can have a good appearance in size and shape when the door is opened.
Therefore, the cushion clip used in the glove box should include the following characteristics in order to provide the functions described above.
(a) When the door is closed, the cushion clip can be appropriately compressed so as to generate a reaction force that is capable of preventing the glove box from vibrating.
(b) The cushion clip can generate a large reaction force when a large load is applied thereto.
(c) In order to generate a desired (required) reaction force regardless of magnitude of the dimensional error of the door, the cushion clip can generate a substantially constant reaction force over a wide range of amount of compression.
(d) The cushion clip is small and does not have an irregular shape.
One drawback of not having the characteristics described above include, for example, that the door of the glove box cannot be sufficiently prevented from vibrating. This may lead to noise generation. Further, the door cannot be smoothly closed.
Thus, the cushion clip used in the glove box should include the following characteristics with regard to a relation between the reaction force and the amount of compression.
(i) In an initial compression period of the cushion clip, as the amount of compression is increased, the reaction force can be quickly increased such that the desired reaction force can be quickly obtained.
(ii) In a middle compression period of the cushion clip, which corresponds to a period after the reaction force reaches a lower limit of the desired reaction force, as the amount of compression is increased, the reaction force can be slowly or gently increased.
(iii) In a terminal compression period of the cushion clip, which corresponds to a period after the reaction force reaches an upper limit of the desired reaction force (after the amount of compression reaches a desired amount of compression), as the amount of compression is increased, the reaction force can be quickly increased.
Further, a relation between the reaction force and the amount of compression in an ideal cushion clip is shown in FIG. 13 as an ideal reaction force line. As will become apparent from FIG. 13, the ideal reaction force line may preferably include an initial compression range (a range A-B), a middle compression range (a range B-E) and a terminal compression range (a range E-).
A reaction force at a point B in the ideal reaction force line corresponds to the lower limit of the desired reaction force (which will be referred to as a minimum reaction force). When the cushion clip is compressed until the minimum reaction force can be generated, the cushion clip is capable of effectively preventing the door of the glove box from vibrating and generating noise while the vehicle is moving. Further, a reaction force at a point E in the ideal reaction force line corresponds to the upper limit of the desired reaction force (which will be referred to as a maximum reaction force). When the cushion clip is compressed until the maximum reaction force can be generated, a lock device of the door cannot be easily unlocked. Further, when the cushion clip is further compressed until a reaction force greater than the maximum reaction force is generated, the lock device of the door is subjected to an excessive load. This may lead to malfunction of the lock device.
Thus, the desired reaction force substantially corresponds to a reaction force between the minimum reaction force and the maximum reaction force. As will be appreciated from FIG. 13, the middle compression range (the range B-E) of the ideal reaction force line is very wide. That is, in the ideal cushion clip, a range R of the amount of compression in which the desired reaction force can be generated is very wide. This means that the ideal cushion clip can generate the desired reaction force over a wide range of the amount of compression. Further, the range R of the amount of compression may be referred to as an effective stroke of the ideal cushion clip.
A known cushion clip is taught, for example, by Japanese Laid-Open Patent Publication No. 2006-153083. The cushion clip includes a hollow cushioning portion. The cushioning portion has a protrusion that is formed in a bottom wall portion thereof.
Further, another known cushion clip is taught, for example, by Japanese Laid-Open Patent Publication No. 2007-225093. The cushion clip includes a cushioning portion having an accordion side wall. The cushioning portion has a protrusion that is formed in a bottom wall portion thereof.
A cushion clip is shown in FIG. 14, which cushion clip has the substantially same construction as the cushion clip taught by Japanese Laid-Open Patent Publication No. 2006-153083. The cushion clip 101 includes a cushioning portion 110 that is capable of absorbing an impact, and an engagement portion 120 that is capable of attaching the cushioning portion 110 to a stationary member. The cushioning portion 110 is made of a soft material having elasticity. Conversely, the engagement portion 120 is made of a hard material having a predetermined rigidity. Further, the cushioning portion 110 has a side wall portion 112 having a cone-shaped outer surface 170 and a vertically extending cylindrical inner surface 180. In addition, the cushioning portion 110 has a cavity portion 140 that is defined by the inner surface 180 of the side wall portion 112. The cushioning portion 110 has a substantially circular opening 160 that is defined by an upper end periphery 112a of the side wall portion 112. Further, the cushioning portion 110 has a bottom wall portion 113 that is integrated with the side wall portion 112. The bottom wall portion 113 has a projection 190 that is upwardly projected from the bottom wall portion 113 toward the circular opening 160.
In the cushion clip 101, the side wall portion 112 can be deformed due to compressive performance thereof, so as to generate a reaction force. Therefore, when a load applied to the cushion clip 101 is changed, the reaction force generated by the deformed side wall portion 112 can be changed in a quadratic curve. As a result, a range of amount of compression in which desired reaction force can be generated is very narrow. Therefore, the cushion clip 101 cannot generate the desired reaction force over a wide range of the amount of compression. That is, an effective stroke of the cushion clip 101 is very short.
In addition, the conventional product of the cushion clip 101, shown in FIG. 14, has the projection 190 provided for the gate. Thus, the range of the stroke is small and the reaction force becomes large before the door is closed. Further, because a diameter of the projection 190 is thin, the projection 190 cannot work well as a stopper and cannot prevent interference between the door and the glove box.
Therefore, there is a need in the art for further improved cushion clips.